Gearing arrangements are known which are used in mowing knife cutting units on mowing attachments of combine harvesters. Such cutting units can comprise gearing arrangements boasting a plurality of eccentric drives arranged in rows, wherein the drive of the mowing knives of a mowing knife cutting unit is realized by eccentrically rotating journals or mowing knife drive journals on the eccentric drive, the rotary motion of the mowing knife drive journal being converted into a linear motion for the mowing knife. An eccentric drive of this type for a mowing knife cutting unit is disclosed, for example, in DE 10 2006 005 354 A1.
In the conversion of the eccentric rotary motion of the mowing knife drive journal into a linear motion for the mowing knife, special connecting arrangements are necessary which have the characteristics necessary for the conversion.
Such a connecting arrangement is exhibited by DE 10 2006 010 825 A1. This discloses a connecting arrangement between a mowing knife drive and a mowing knife which is moved linearly to and fro, an annular connecting element being configured which is slotted over the circumference. The connecting element in turn receives an intermediate ring, which is likewise slotted on its circumference. The intermediate ring here encloses the outer race of a rolling bearing, the rolling bearing being radially supported on the mowing knife drive journal. The connecting element is provided at its slot with a clamping screw, by which the connecting element is clamped to the intermediate ring and the outer race of the rolling bearing. The connecting element thus constitutes a clamping device. The connecting element is configured in one piece with the shaft of a mowing knife carrier, a corresponding mowing knife being able to be fastened on the mowing knife carrier. The inner face of the intermediate ring and the outer face of the outer race are spherically configured and allow a slight adjustable axial inclination of the intermediate ring relative to the rotation axis of the rolling bearing, so that the mowing knife carrier, or a mowing knife fastened thereon, is adjustable in terms of its angular position to the mowing knife drive journal or to the rotation axis of the rolling bearing. It is envisaged that the adjustment is made by loosening the clamping screw on the connecting element, so that the intermediate ring can be adjusted relative to the outer race. Following the adjustment, the connecting element is clamped to the intermediate ring and to the outer race of the rolling bearing respectively, so that the connecting element and the mowing knife drive journal are fixedly connected to each other.
The connecting arrangement disclosed in DE 10 2006 010 825 has the following characteristics, which can be detrimental in the event of prolonged operation of the mowing knife cutting unit: the slotted construction of the connecting element and of the intermediate ring makes sealing against the environment considerably more difficult, so that a contamination and regular lubrication of the rolling bearing is inevitable. To this end, complex lubrication bores in the mowing knife drive journal are necessary. The necessary adjustment of the mowing knife carrier is made during assembly of the connecting arrangement and is fixedly set during operation. Thus already light operating loads on the moving knife carrier cause wear producing loads on the rolling bearing which may axially overload said rolling bearing during operation, the rolling bearing being configured as a radial bearing. As a result of the tightly clamped connection between the connecting element and mowing knife drive journal via an intermediate ring, an axial displacement or adjustment of the connecting element relative to the rotation axis of the rolling bearing or longitudinal centre axis of the mowing knife drive journal is possible only to a very limited extent. Not least, the disclosed connecting arrangement has a high multiplicity of parts and corresponding maintenance complexity.
The object of the invention is seen in defining a connecting device of the type stated in the introduction, by which the aforementioned drawbacks are partially or totally eliminated.
The object is achieved according to the invention through the teaching of patent claim 1. Further advantageous embodiments of the invention are provided by the sub-claims.